Custom colors ignored during transitional period

I've noticed that when Flux is in the middle of a transition (specifially Sunset -> Bedtime colors) that you cannot override the setting during this period. What happens is that while Flux is slowly lowering the color temperature, it does not listen to any changes from the slider. As soon as the mouse is released after moving the slider, the temperature resumes dropping to the planned color instead of listening to the new change -- even when switching to "Custom Colors" mode.

The only workaround I've found is to enable Fast Transitions, so that way once the color drops it will be over quickly and then I can manually set it.

I believe this is a bug because I don't recall this happening before I updated to v39.94. I'm on OS X 10.10.5.